Merge pull request #26 from dwhelan/persistence

Check for existing persistent cache files on demand

README.md

@@ -169,9 +169,6 @@ Billy.configure do |c|
   c.cache_path = 'spec/req_cache/'
 end
 
-# need to call this because of a race condition between persist_cache
-# being set and the proxy being loaded for the first time
-Billy.proxy.restore_cache
 ```
 
 `c.ignore_params` is used to ignore parameters of certain requests when

lib/billy/cache.rb

@@ -6,7 +6,6 @@ module Billy
   class Cache
     def initialize
       reset
-      load_dir
     end
 
     def cacheable?(url, headers)
@@ -18,11 +17,26 @@ def cacheable?(url, headers)
     end
 
     def cached?(method, url, body)
-      !@cache[key(method, url, body)].nil?
+      key = key(method, url, body)
+      !@cache[key].nil? or persisted?(key)
+    end
+
+    def persisted?(key)
+      Billy.config.persist_cache and File.exists?(cache_file(key))
     end
 
     def fetch(method, url, body)
-      @cache[key(method, url, body)]
+      key = key(method, url, body)
+      @cache[key] or fetch_from_persistence(key)
+    end
+
+    def fetch_from_persistence(key)
+      begin
+        @cache[key] = YAML.load(File.open(cache_file(key))) if persisted?(key)
+      rescue ArgumentError => e
+        puts "Could not parse YAML: #{e.message}"
+        nil
+      end
     end
 
     def store(method, url, body, status, headers, content)
@@ -35,15 +49,14 @@ def store(method, url, body, status, headers, content)
         :content => content
       }
 
-      @cache[key(method, url, body)] = cached
+      key = key(method, url, body)
+      @cache[key] = cached
 
       if Billy.config.persist_cache
         Dir.mkdir(Billy.config.cache_path) unless File.exists?(Billy.config.cache_path)
 
         begin
-          path = File.join(Billy.config.cache_path,
-                           "#{key(method, url, body)}.yml")
-          File.open(path, 'w') do |f|
+          File.open(cache_file(key), 'w') do |f|
             f.write(cached.to_yaml(:Encoding => :Utf8))
           end
         rescue StandardError => e
@@ -55,20 +68,6 @@ def reset
       @cache = {}
     end
 
-    def load_dir
-      if Billy.config.persist_cache
-        Dir.glob(Billy.config.cache_path+"*.yml") { |filename|
-          data = begin
-                   YAML.load(File.open(filename))
-                 rescue ArgumentError => e
-                   puts "Could not parse YAML: #{e.message}"
-                 end
-
-          @cache[key(data[:method], data[:url], data[:body])] = data
-        }
-      end
-    end
-
     def key(method, url, body)
       url = URI(url)
       no_params = url.scheme+'://'+url.host+url.path
@@ -85,5 +84,9 @@ def key(method, url, body)
 
       key
     end
+
+    def cache_file(key)
+      File.join(Billy.config.cache_path, "#{key}.yml")
+    end
   end
-end
+end

lib/billy/proxy.rb

@@ -54,8 +54,8 @@ def reset_cache
     end
 
     def restore_cache
+      warn "[DEPRECATION] `restore_cache` is deprecated as cache files are dynamincally checked. Use `reset_cache` if you just want to clear the cache."
       @cache.reset
-      @cache.load_dir
     end
 
     protected

lib/billy/version.rb

@@ -1,3 +1,3 @@
 module Billy
-  VERSION = "0.2.1"
+  VERSION = "0.2.2"
 end

spec/lib/proxy_spec.rb

@@ -121,6 +121,19 @@
         r = http.get('/foo')
         File.exists?(cached_file).should be_true
       end
+
+      it 'should be read initially from persistent cache' do
+        File.open(cached_file, 'w') do |f|
+          cached = {
+            :headers => {},
+            :content => "GET /foo cached"
+          }
+          f.write(cached.to_yaml(:Encoding => :Utf8))
+        end
+
+        r = http.get('/foo')
+        r.body.should == 'GET /foo cached'
+      end
     end
 
     context "disabled" do